First, there is no "support team" here, just a community. That is, you're the member of this team as everyone else.
Next, about the questions.
1. Can't answer without seen the application. If the "animation dimension", Year in your case, has non-0 values, there shouldn't be a problem. If you upload the application, I'll be able to help. Or somebody else of the "support team" .
2. Not sure what you mean here, sorry. May be you want to select a country or two and run animation?
3. It is possible. Add the third expression to the chart to calculate total waste in tones. And, select chart style that shows different bubble types (it is obvious on the Style tab).